The effects of partial and complete masculinization on the sexual differentiation of nuclei that control lordotic behavior in the male rat.
Male rats, under certain experimental conditions, may show lordosis, the typical expression of female sexual receptivity. This work studies the sexual morphological pattern of facilitatory and inhibitory structures that control lordosis. Three groups of males were neonatally subjected to a gradient of androgen exposure (castrated plus injected oil (GxM+oil); castrated plus androstenedione treated (GxM+AND); and sham operated [CM]); a group of control females (CF) was also added. Lordotic response after these different hormonal and neonatal surgical treatments, as well as the volume or number of neurons in facilitatory (ventromedial nucleus of the hypothalamus [VMN]) and inhibitory (the intermediate region of the lateral septum [LSi] and accessory olfactory bulb [AOB]) nuclei involved in lordosis was studied in adults. The inhibition of lordosis in the males seems to be associated to the neonatal presence of testosterone and the consequent masculinization of the VMN, VMNvl, LSi and AOB. It is suggested that one of the functions of the sex differences consistently seen in these structures might be to inhibit the lordosis response in the male.
Segovia
Santiago
S
Departamento de Psicobiología, UNED, Madrid, Spain.
Garcia-Falgueras
Alicia
A
Perez-Laso
Carmen
C
Pinos
Helena
H
Carrillo
Beatriz
B
Collado
Paloma
P
Claro
Francisco
F
Guillamon
Antonio
A
D000735:Androstenedione / Q000494:pharmacology; D000818:Animals; D002452:Cell Count; D003627:Data Interpretation, Statistical; D005260:Female; D005262:Feminization; D008297:Male; D009474:Neurons / Q000502:physiology; D009830:Olfactory Bulb / Q000033:anatomy & histology / Q000166:cytology / Q000502:physiology; D009919:Orchiectomy; D051381:Rats; D020665:Septum of Brain / Q000033:anatomy & histology / Q000166:cytology / Q000502:physiology; D012733:Sex Differentiation / Q000502:physiology*; D012726:Sexual Behavior, Animal / Q000502:physiology*; D014697:Ventromedial Hypothalamic Nucleus / Q000033:anatomy & histology / Q000166:cytology / Q000502:physiology
D000735:Androstenedione